Automatic telephone system



July 9, 1935.' I .AwlLsoN AUTOMATIC TELEPHONE SYSTEM Filed Jan. so, 1932 5 sheets-,sheet 1 INVENTOR.

MAN

60W/ard W J-uly 9, 1935. L. wlLsoN I 2,007,736

AUTOMATIC TELEPHONE vSYSTEM Filed Jan, 3 0, 1932 5 sheets-sheet 2 aff/@2,

gewaar/d @ff/6070,

A TTORNE Y.

July 9,1935.

1 L. WILSON 2,007,736 l AUTOMATIC TELEPHONE SYSTEM Filed Jn. 30, 1932 5 Sheets-Sheet-S L5'-/ l 395 j? C396 wfg/'97 5 INVENTOR. 60W/ard Mfr/dma July 9, 1935.- l.. WILSON AUTOMATIC TELEPHONE SYSTEM 5 Sheets-Sheet 4 Filed Jan. 30, 1932 @hw www QN NINN July 9, 1935. I wlLsoN 2,007,736

AUTOMATIC TELEPHONE VSYSTEM y Filed Jan-` 50, 1932 5 Sheets-Sheet 5 3 l y, .527 G INVENToR. gewaagd 144155070,

" ATTORNEY.

Patented July `9, 1935 AUTOMATIC TELEIEHONEv SYSTEM v Leonard Wilson, Salt Lake City, Utah,.a`ssignor, by mesneas'signments, to Milton S; Friendly,

Chicago'ylll.; Oscar N.

Friendly, Salt Lake City,

Utah, and Central Republicirust'- ConpanyV Chicago, Ill., a corporationof Illinois, trustees under the will of Herbert M.' Friendly, deceased Application January 30, 1932, Serial No. vESQQSAZ-ii I p Y 30 Claims, TIh-e present invention relates ink general to automatic .telephone systems andA more partic-y ularly to measured service automatic systems. Oneof the objects of the present invention is to provdea novel zone metering systemin which a charge is made in accordance between subscribers.

`Another Objectis to provide means whereby the zone metering charge may be assessed against the calledsubscribers telephone.

Another object is to provide 4mechanism b which the called subscriber can reverse the periwith the distance odicalmeteringcharge from the calling subscrib ers line to his own irrespective ofnwhether thev calling and called subscribers A are in the same exchange or not. f

Another object is to provide mechanism whereby this reversal may be made by the called subscriber at any time during his conversation with the vcalling subscriber. 'v

Another object is to provide a method of mak' inga chargeV to the line of the calledsubscriber at his option in accordance with/the'length of the conversation and also in accordance with theninterV-exchange trunk lines employediortlfle ins charges in telephone .connectionswith a restricted class of called subscribers. y

.A still further object'` is to apprise the subscribe ers, irrespective of whether' they are located in the same exchange or' not, of .the line /torwhich the `charge is being made.

device which may be associated with the inter'- cxchange trunk line or any other trunk line that will serve to add to the usual metering charge lines in a simple and highly expeditious'manner. There are other objects of my invention which, l together with the foregoing, will be "described in the detailed specification that isto follow taken in conjunction -witlnthe accompanying drawings and forming,apartthereoff The present inventionvis an improvement yon Still another object is to provide' a translating (Cl. NSL-'7.1) v t the co-pending application of Herbert M. Friendly, Serial `No5'715,135., led November 14, 1931.

My invention has been illustrated in anlautomatic telephone system of the so-called Strowger type employing `lirst and second selectors and connectors. lectors may be employed if necessary or desirable to provide a greater number of subscribers. That is, third and fourth .selectorsmay be employed in each` exchange ifV it is desired, to provide for selection in a ten thousand (10,090) line exchange. withselection between `any one of one hundred t100) exchanges making atotal capacity for the wholevsystem cia-million (1,0()(25300) lines. The

manner in which the`.trunking capacity of the systemrcan be increased or altered is well-known and need not be described. In practicing the invention, aV-metering` device is provided for eachv line which it is desired to make a charge against. A timing switch is associated with each rst selector and with each connector in order -to bringv about the. timing of the conversation. A mechanism is associated withleach interexchange trunk line at both the incoming and outgoing ends to assess additional-charges forv the use oi trunks employed in the connections. This arrangement limits the additional charging mechanism to use on interexchange calls only where the distance between subscribers is greater and more equipment is employed. While the invention has been illustrated in connection with one way inter-cnice trunk lines, it will be obvious that it may be em-` ployed in connection with two-way trunk lines. A push button-is provided at each subscribers` telephone so that when that telephone is called the` called subscriber thereat may reverse the charge.v

y Briefly, thev operation of my invention proceeds as follows:v l v i The connection between the callingrand called subscriber is accomplishedin the usual manner through the calling subscribers line switch, an idle first selector, an idle second selector and a connector. When the subscribers are connected, the timing switch' individual to the first selector is operated periodically `to actuate ythe meter associated with .the calling subscribers line. the event the called subscriber is one of those subscribers "who may reverse the charges he presses the push button at his telephone, lwhich brings about the cessation of the operation of the timing switch at the rst selector and the initiation of the operation of the timing switch individualto the connector. The operation of the timing switch individual to the connector causes Obviously, a greater number of se.I

Inv

the meter associated with the called subscribers line to be actuated periodically. Audible signals are applied to the line at short intervals before the charge is made, the tone being of one pitch to inform the called subscriber if the charge is being made against him and of another pitch to inform the calling subscriber if the charge is being made against him. The foregoing is the operation of a call between subscribers, local to the same exchange. In the eventl the connection is one between lines located in different exchanges, the connection is accomplished in the usual manner, including the calling subscribers line switch, an idle first selector, a repeater associated with a trunk line extending to the distant exchange, an

incoming second selector at that exchange and an f In the event the called subscriber is one of thosev subscribers who may reverse the charges from the calling line to his own, he presses the push button at his telephone which brings about the cessation of the operation of the timing switch at the first selector and the effective operation of the timing switch individual to the connector.

The operation of the timing switch individual to the connector causes the-meter associated withy the called subscribers line to be actuated periodically. After each metering impulse, the timing mechanism associated with the trunk line at `its incoming end in the exchange local to the called subscriber is effective to bring about an additional metering charge in accordance with the distance between exchanges. In this manner a charge is made to either the calling or called telephones in accordance with the amount of equipment employed for the connection and the distance between the various exchanges in the system. That is, a zone metering charge is made dependent not only on the distance but 'on the time employed for the conversation. As will appear more fully hereinafter, another variationv of the charge can be made dependent upon the traic load or the time of day at which the call is made. Audible signals are applied to the connection between the subscribers to indicate when the charge is being made and also to differentiate as to the line the charge is being made against.

Referring now to the drawings comprising Figs. 1 to 5, inclusive, the invention has been illustrated in connection with a simple hundred thousand (100,000) line automatic telephone system of a step by step or Strowger type, wherein the apparatus and circuits are shown by means of the usual conventional diagrams. The sheets are arranged to illustrate the connection between a called and calling subscriber when placed side by side with the similarly numbered conductors in alignment.

In Fig. 1 in the upper left hand corner of the sheet a calling subscribers telephone is illustrated, designated with the reference character T. The telephone comprises the usual transmitter, receiver, switch hook and ringer. In addition, the telephone is provided with a push button |02 whose contacts normally short circuit a resistor included in the line circuit. Reference character LS designates the usual type of rotary line switch individual to the line of the subscriber at sub-station T. The line switch is provided with the usual line relay |09, switching relay |08 and motor magnet I I4. The motor magnet I I4 is operated to advance the switch wipers I I to I I3, inclusive, step by step over associated bank contacts such as |2| to |24, inclusive, in search of an idle trunk. A metering device |01 of any usual or well known type is associated with each line switch. I'he rotary switches LS have access to trunk lines extending to rst selectors such as the first Selector S.

The selector S is generally of the usual and well known Powell type, having controlling relays |25 to |32, inclusive, and being provided with the usual vertical magnet |33, rotary magnet |34, and release magnet |35. The selector S has access to I 0 groups of trunk lines terminating in I0 groups of bank contacts |84 and |81, inclusive, accessible to switch wipers |35 to |38, inclusive. A rotary timing switch RS-I, which may be of the same general mechanical construction as the rotary switch LS, is associated with each first selector such as S. The rotary switch RS-I has access to bank contacts which are connected to metering and tone machine mechanism M. The metering and tone machine mechanism M is common to all the metering switches, such as RS-l, associated with the first selector S. 'I'his metering equipment consists essentially of two motor driven shafts |14 and |8I, upon which'are mounted commutating segments |12 and |13 and |15 to |18, respectively. The commutating segments |12, |13, |11 and |18 are connected to the battery, while the commutating segments |15 and |16 go to tone machines and may generate audible signals of different pitch.

The trunk lines terminating in the bank contacts accessible to the first selectors such as S extend to other selectors and also the trunk lines extending through repeaters such as R (Fig. 2) to incoming second selectors such as S-I (Fig. 3) at a distant exchange. Repeaters such as R are generally of the same type as those ordinarily employed in automatic exchanges and are provided with controlling relays 250 to 258, inclusive. A rotary timing switch RS-5 is associated with the trunk line extending to each repeater such as R and is provided with controlling relays 200 to 202, inclusive, a motor magnet 2|8, and switch wipers 2 I2 to 2|4, inclusive. The rotary switch RS- is a timing switch and its switch wipers are adapted to engage a plurality of bank contacts which may be twenty-ve in number in the event the switch is similar to the usual rotary line switches.

The motor magnet 2|8 is adapted to step th'e switch wipers 2|2 to 2|5, inclusive, into engagement with the associated bank contacts. An interrupter 225 is adapted to control the operation of the `motor magnets of the various switches as will appear. The incoming second selector S-I is of the usual and well known type or Strowger switch commonly known as the Powell type, being provided with a vertical magnet 320, rotary magnet 32 I, release magnet 322 and control relays 3| 5 to 3|9, inclusive. The selector S-I is also provided with wipers 338 to 339, inclusive, which haveaccess to bank contacts in ten levels. The trunk lines connected to these bank contacts may extend to connectors such as C (Fig. 4) of the usual step by step type.

A rotary timing switch RS-G is associated with each of the incoming selectors such as Sv| and generally is of identically the same construction as therotary timing switch RS-5 (Fig. 2) previo/usly described. vThis switch is provided with'` control relays 35|) to 352, inclusive, motor magnet` 368 and switch wipers 282 to 2M, inclusive, adaptedto engage the associated bank contacts.

The connector CV is provided with control relays488 to 4|8, inclusive, and the usual vertical magnet 4|2, rotary magnet 4 i3, Aand release magnet 4H.` vThe connectors suchas C are divided into 10 groups, each group having accessto 10D 413..V to 416, inclusive, aboutjts associated bank The bank contacts of the timing switch contacts. are connected to common metering equipment M-Z. The metering equipment M-'2 consists essentially of two motor driven shafts 488 land 489, which are provided with the commutating segments 482, 483, 484 and 487 and 485 and 486,l respectively. The commutating segments 484,I

481, 485 and 486 are connected to the battery, while vthe commutating segments 482 Iand 483 are connected to tone machines capable of generating signals of different pitch. In addition, a common metering device M-|, which consists of a clock driven wiper 48| adapted to engage circular contacts twenty four in number, for each hour of the day. The wiper 48| will bein engagement with la certain particular contact.

As before mentioned, the connector C has access to called telephone lines of 100 called subscribers, such as the subscribers located at stations T-l to T-S, inclusive. Each of the called subscribers lines is` provided with rotary line switches such as RS-- of identically the same construction as the rotary switch LS previously described; The telephone sub-station circuits of the called subscribers such as T-i areof identically the same construction as the telephone substation T previously described, being provided V with the usual transmitter, receiver, `switch hookv and'ringer, and, in addition, push button 556 and resistor 555. A slightly modiiied form of substation circuit is shown at 'IL-2, whereinthe push button 557 is employed to ground one side of the line. The circuit of the telephone sub-station 'I-3 is of the usual type, not being provided with a push button. This is to illustrate the line of acalled subscriber who has free service. The line of the sub-station T--3, in addition to terminating in the contacts ofthe connectorC and other connectors of the same group, terminates fin the rotary line switch RES-4. In addition relays, such as 5H to 5H), are provided in association with this line for the purpose vof preventing the4 telephone subscriber at station 'IL-3 from altering the metering charge of the calling subscriber when in connectionwith his line in any manner.

While the timing switches RS-I and RS-2,

RS- 5 and RS--B associated with the nrst selector S, repeater'R, incoming selector S-| and connector C, respectively, have been illustrated asindividual to these switches, it will be understood that they may be madecomm'on to a group of their respective switches by the use ci finder switches in any suitable or well known manner.

Having briefly described the apparatus .and

circuits shown in the drawings, their detailed operation Ywill now be described. For this purpose,.-

itwill be assumed that the subscriber at substation T desires` to call the subscriber atsubstation T-I. In order to accomplish this result thesubscriber at substation T will remove his receiver from the switch hook, thereby completinga circuit which extends from ground by way of back contact and armature il, line conductor I8 l, contacts of push button it?, switch hook contacts', receiver and transmitter in series, line conductor |80, armature and its back ccntact,.

winding of line relay |69, and thence to battery. 'Ihe slow acting relay m9 is energized over this circuit'and serves to complete a circuit which eX- tends from ground by way" of armature iiiii and its front contact, switching relay |88, back con tact and armature of motor magnet i i4, and then through the winding of this magnet to battery, and at armature H9 and its front contact serves to connect the test wiper l to the above circuit at a point midway between the switching relay |88 andrmotor magnet i I4. In the event that the switch wipers l l!! to H3, inclusive, are in engagement witha busy trunk line, ground will be connected tothe bank contact associated with the vtest wiper lli, and the motor magnet H4 will be operated to advance the switch wipers i8 to I3, inclusive, until they are in engagement with the bank contacts associated with an idle trunk line. At this time there will be a circuit completed for the switching relay |88 in series with the motor magnet H4; The switching relay Hi8 upon operating' connects the meter |81' to the metering wiper i0 at armature i5 and its front contact, opens the testcircuit of the motor magnet I i4 atarmature i8 and at the front contact oi-this armature prepares a holding circuit for the switching relay |08. At armatures lit and |I'i the operation of the switchingl relay |83 serves to open the circuit of the slow acting line relay |89 'and to extend the talking conductors and lill to the Wipers ||2 and H3. It will be assumed that the trunk selected by the operation of the line switch is the trunk line terminating in' the bank contacts |2| lto |24, inclusive. Consequently, upon the extension of the talking conductors |88 and lill as described there will be a circuit completed extending from ground through the lower winding of .the line relay |25, of the selector S, back contact and armature |48, bank contact |24, thence through the calling subscrib ervs telephone, bank contact |23, through the lower ywinding of the electropolarized relay |21,

armature lillV and its back contact, and thence` through the upper winding of the line relay r|29 to battery. The line relay |29 is energized over this Vcircuit and upon operating opens a point in the circuit of the release magnet |35 at arma,-

ture |58 and its back contact, and at the front contact of this armature completes a circuit for the slow acting relay |38. The slow acting relay i-Supon operating disconnects ground from certain bankcontacts in the timing switch RS--i at armature I5! and its back contact, at the front contact of this armature connects ground to the holding or release trunk conductor, and at arma' ture |52v and its front contact prepares a circuit for thevertical magnet |33. The connection of ground to the release trunk conductor serves to establish a holding circuit extending back to the switching relay |88 of the rotary switch LS and the motor magnet I4 in series, in order to maintain the switching relay |88 energized after the deenergization of the slowv acting line relay |39.

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The application of ground to the release trunk also completes the circuit for the polarizing winding of the electro-polarized relay |21.

When the calling subscriber at sub-station T operates his calling device CD in accordance with the rst digit of the called subscribers number a series of interruptions are produced in the circuit of the line relay |29 which retracts its armature a number of times corresponding to the number of interruptions. At each retraction of its amature there is a circuit completed which extends from ground by Way of armature |50 and its back contact, back contact and armature |49, armature |52 and its front contact, winding of slow acting relay 3|, and vertical magnet |33 to battery. The vertical magnet is operated to raise the switch wipers |35 to |38, inclusive, opposite the proper level of the bank contacts. At the iirst ofi normal step of the switch, the off normal springs |56 and |51 are shifted to prepare a circuit for the rotary and release magnets. 'I'he slow acting relay |3| is energized to open a point in the circuit of the rotary magnet |34 at armature |53, and to complete a circuit which extends from ground by way of armature |5| and its front contact, armature |53 and its front contact, armature |94 and its back contact, working contact of off normal spring |56 and said spring and interrupter relay |32 to battery. The interrupter relay |32 is energized over this circuit to establish a locking circuit for itself at armature |54 and to prepare the circuit for the rotary magnet |34 at armature |55.

A` short interval after the calling device has returned to normal position the relay |3| is deenergized to complete a circuit for the rotary magnet |34 over a path that extends from ground by way of armature |5| and its front contact, armature |53 and its back contact, armature |55 and its front contact, and rotary magnet |34 to battery. The rotary magnet I 34 is energized over the above circuit and operates to advance the switch wipers |35 to |38 inclusive, one step into engagement with the first set of bank contacts on the level selected. A further result of the operation of the rotary magnet |34 is that at armature |94 the circuit of the interrupter relay |32 is opened and it de-energizes. The de-energization of the interrupter relay |32 opens a point 1 in the circuit of the rotary magnet at armature and at armature |54 opens a point in its locking circuit. A test circuit is now established, which extends from the test wiper |36 by way of armature |46 and its back contact, armature |94 and its back contact, working contact of offnormal spring |56, and said spring and relay |32 to battery. If the trunk line with which `the switch wipers |36 to |38, inclusive, are in engagement is busy, there will be a ground/potential upon the bank contact engaged by the switch wiper |36 and the relay |32 will be energized over the above circuit to establish a locking circuit for itself at armature |54 and to complete a circuit for the rotary magnet at armature |55. The rotary magnet |34 upon operating opens the circuit of the interrupter relay |32, which is deenergized to interrupt the circuit of the rotary magnet. The alternate operation of the interrupter relay |32 and the rotary magnet |34 continues until the switch wipers |35 to |38, inclusive, are advanced into engagement with the bank contacts associated with an idle trunk line, which it will be assumed are the bank contacts |84 to |81, inclusive. When the switch wipers are brought into engagement with this set of bank contacts there will be no ground potential upon the bank contact |85 and no circuit will be completed for the interrupter relay |32. The circuit is now established which extends from ground by way of armature 5| and its front contact, winding of switching relay |28, armature |94 and its back contact, working contact of off-normal spring |56 and said spring and interrupter relay |32 to battery. On account of the high resistance of the relay |28, the interrupter relay |32 is not operated over this circuit. The switching relay |28 upon operating opens the point in the circuit of the release magnet at armature |49, opens a point in the testing circuit at armature |46, and at armatures |41 and |48 disconnects the talking circuit extending to the calling telephone from the windings of the line relay |29 and at the front contacts of these armatures extends the calling line through the wipers |31 and |38, bank contacts |86 and |81, trunk conductors |91 and |98, normally closed springs controlled by armatures 260 and 26| to the upper and lower windings of the line relay 25| of the repeater R.

The line relay 25| of the repeater R is energized over a circuit including the calling line and operates to complete a circuit for the slow acting relay 252 at armature 263 and to complete a bridge across the trunk conductors 280 and 26| at armature 264. The slow acting relay 252 is energized to prepare a circuit for the slow acting relay 253 at armature 268 to complete another point in the bridge circuit across the trunk conductors 280 and 28| at armature 266 and to complete the circuit for the polarizing winding of the electro polarized relay 254 at armature 261. A further result of the operation of the relay 252 is that at armature 261 there is a holding circuit established for the switching relay |28 of the selector S and the holding relay of the line switch LS. This holding circuit is established prior to the de-energization of the slow acting relay |30 of the selector S which occurs a short interval of time after the de-energization of the line relay |29 following the operation of the switching relay |28.

The bridge across the trunk conductors 280 and 28| establishes a circuit for the line relay 3| 6 of the incoming selector S-| over a path that may be traced from ground, lower winding of line relay 3|6, back contact and armature 325,

trunk conductor 28|, front contact and armature 264, right-hand winding of impedance relay 258, normally closed springs controlled by armature 262, winding of electro-polarized relay 254, normally closed springs controlled by armature 269, front contact and armature 266, trunk conductor 280, armature 324 in its back contact and upper winding of line relay 3|6 to battery. The line relay 3|6 is energized over this circuit in the incoming selector S-I and operates to complete a circuit at armature 321 for the slow acting relay 3|1. 'I'lie slow acting relay 3| 1 is energized to open a point in the circuit of the release magnet 322 at armature 329 and to prepare a circuit for the vertical magnet 320 at the front contact of this armature.

Another result of the operation of the relay 3| 1 is that at armature 328, a circuit is prepared for the switching relay 3|5 and for the rotary magnet 32|.

When the calling device at the sub-station A is operated in accordance with the next digit of the called subscribers number, which it will be assumed is the digit 2, two interruptions will be produced in the circuit of the line relay 25| of to battery.

In the repeater R, a short interval of time after the cessation of the operation of the line relay 25|, the slow acting relay 253 is de-energized to restore the original bridge across the cross conductors 280 and 28|.

When the calling subscriber operates his calling device in accordance with the last digit of the called subscribers number, there will be another series of interruptions produced in the circuit of the line relay 25| of the repeater R. The line relay 25| of the repeater will retract its armatures 263 and 264 a. corresponding number of times. By the operation of the armatures 263, the slow acting relay 253 will be energized to charge the bridge across the trunk conductors in the manner described. By the operation of the armatures 264 a plurality of interruptions will be produced in the bridge across the trunk conductors 280 and 28| bringing about the de-energization of the line relay 404 of the connector C in the distant exchange a plurality of times. At each de-energization-of the line relay 404 there is a circuit completed, which extends from ground by way of armature 43| and its back contact, armature 433 and its front contact, off-normal springs 4|5, armature434 and its back contact, back contact and armature 44|, back contact and armature 454, and rotary magnet 4|3 A branch of this circuit extends through the slow acting relay 409 to battery. The rotary magnet 4| 3 is operated a plurality of times to advance the switch wipers 4|4 to 4|1, inclusive, into engagement with the bank contacts associated with the line ofthe subscriber at sub-station T-l, which it will be assumed are the bank ycontacts 492, 496, 494 and 498, respectively. 'I'he slow acting relay 409 is energized in parallel with the rotary magnet 4|3 and operates at armature 443 to prepare a circuit for the busy test relayv 408 and to prepare an alternative circuit for itself and the rotary magnet at armature 444 and its front contact, exclusive of the armature 44|. This result is for the purpose of maintaining the circuit of the rotary magnet, irrespective of the energization of the busy test relay 408 in the switch wipers 4|6 to 4|9 passing over busy lines. This result is brought about by the test wiper 4| 1 encountering a Iground potential upon bank contacts it rotates over-,and bringing about the operation of the relay 408.

It will rst be assumed that the line of the called subscriber at sub-station T-|\ is busy.

l In this instance there will be a ground potential vin the rotary magnet circuit at armature 44| and at armature 442 applies the busy tone to a conductor extending to the calling telephone. A short interval after the cessation of the last series of impulses the slow acting relay 409 is de-energized to open another point in the rotary magnet circuit at armature 444 and to establish the locking circuit of the relay 408 at the normally closed springs controlled by armature 443. This locking circuit may be traced from ground by way of front contact and armature 4| 4, armature 440 and its front contact, normally closed springs controlled by armature 443, armature 452 and its back contact and relay 400 to battery. At the repeater R, a short interval of time after the calling device at the calling sub-station restores to normal the slow acting relay 253 is deenergized to restore the bridge across the trunk conductors 280 and 26| to its normal condition.

When the calling subscriber hears the busy signal, he will replace his receiver upon the switch hook, thereby bringing about the de-energization Vof the line relay 25| in the repeater R. As a result of the de-energization of this relay, the circuit of the slow acting relay 252 is opened at armature 263 and the bridge across the trunk conductors 280 and 28| is opened at armature 264. As a result of the opening of the bridge, the line relay 404 in the connector C at the distant exchange will be de-energized. Immediately upon the de-energization of the slow acting relay 252 in the local exchange, ground will be removed from the release trunk conductor |96 thereby opening the circuits of the switching relays |28 of the selector S and |00 of the line switch LS. In the selector switch S the switching relay |28 is de-energized to complete a circuit for the release magnet |35 over a path which extends from ground by way of armature |50 and its back contact, back contact and armature |49, armature |52 and its back contact, working contact of off-normal spring |51 and said spring, switch wiper |60 of timing switch RS-l, first bank contact, and release magnet |35 to battery. The release magnet |35 is energized to restore the switch wipers |36 to |38 to normal. The disconnection` of ground from the release trunk conductor |96 also brings about the de-energization of the switching relay |08 of the rotary line switch RS, which upon de-energizing connects the calling line to the line relay |09 so as to prepare the rotary line switch for another call.

At the distant exchange, the line relay 404 is de-energized to retract its armature 43|. A short interval after the retraction of the armature 43|, Vthe slow acting relay 405 is de-energized to complete a circuit for the release magnet over a path which may be traced from ground by Way of armature 43| and its back contact, armature 433 and its back contact, armature 423 and its back contact, oil-normal spring 451 and its working contact, back contact and armature 41| and release magnet 4|| to battery. The release magnet 4|| is energized to restore the switch wipers 4| 6 to 4|9, inclusive, to their normal position in the usual manner. The de-energization of the slow acting relayv 405 also disconnects ground from the release trunk conductor 396 thereby opening the holding circuit of the switching relay 3|5 o1' the incoming selector switch S-l The relay 3 I5 is de-energized to complete a circuit for the release magnet 322 at armature 326 over a path that extends from ground by way of armature 321 and its back contact, back contact and armature 326, armature 329 and its back contact, working contact of off-normal spring 330 and release magnet 322 to battery. The release magnet 322 is `at they calling station.

energized to restore the switch wipers V3,36 to v339, inclusive, to normal at which time the circuit of` the release magnet 322 is opened. atv thev off'- normalspring 33d 'In the'fore'going manner, the switches involved in the-establishment of the Vconnection between the sub-stationsT and T-l are restored to normal responsive tothe replacement of the receiver It will now be assumed Vthat the/line-v of the sub-station T-l when called by the subscriber `atsub-station T was idle. In this instance when the switch wipers -t l 6 to #i I9 inclusive, of the connector C `'are brought into. engagement with the `bank contacts @92, ISEQiSd and 498, there will. Lbe no ground potential upon the test contact'll96 energized to complete a circuit for the switchingrelay Mii over a path which extends from ground tion T removes his receiver, whereupon there isr 'by'y way of ,front contact and armature BM, armature Mt and its Aback contact, lower winding of relay'dlll, back contact and armature M3, test wiper `Ml', bank contactfdQE, conductor 505, relay Efitjback contact and armature 55d, and motor magnet Stil to battery.4 The switching relay Gli) is energized over `this circuit and operates to establish a lockingcircuit for itself atarmature 453 to open a point in the locking circuit of the busy ltest vrelay M39 at armaturefl to open a point Vin the circuit of therotary magnet at armature i554 `to apply ground to thetest wiper` 4H at armaturellb and'tofcomplete the ringing circuit at armatures itil, 35i and 45S. The-application-ofI -ground tov the-busy test wiper applies a 'full ground potential to the"conductor lEll to busy the called' line.

'TheV switching relay 546 in the line switch FdS-3 associated with the called sub-station T`l `is energized, but by reasonof an inter-locking device controlled by thefarmature of the line re-l layt, the armaturesftfil, i, 549 and 551 Vare only partially operated suicient to dis-'engage Vtheir back contactsbut not to engage their front contacts. lin this mannerthe called line is cleared of attachments. A ringing circuit is now established which extends from ground by way of back contact and armature 439, front contact andarmature 6155,' wiperlll, bank contact 498, conductor 5M over the -line of thecalled telephone throughv its ringer, condenser, switch hook, springs of push button 565, over lineconductor, conductor 5l2, bank contact 49d, wiper M8, armature 45t and its front contact, armature 33t and its back contact, upper winding of ring cut-off relay till and thence t'o battery either through the ringing generatorR orlthearmature Si and The relay itil is not operated cuit. Ringing current is intermittently applied to the called line untilthe subscriber at sub-staa circuit .for direct current over the line lof the Ycalled telephone and the relay lOl is energized to establish a locking circuit for itself at armature ttl. This locking circuit is. established before any other armature or springs of the relay are operated.` The relay il? upon voperating opens a point in its own energizing vcircuit at armature dit at the front contact or" this armature,

completes a point in the talking circuit, corn- `pletesv a point in the circuit of a vsupervisor signal at" armature 438, opens a point in the ringing `circuit at armature 439 and-at thel front. contact oftthisarmature completes the talking circuit. The Atalkingv circuit extends to the called telephone over the heavy conductors shown in the drawings. 'The calling telephone is supplied with talking lcurrent .through theV windings' of the line relay 25| inthe repeater R while the .called telephone is supplied with talking current throughrthe .windings of the relays 45MB and 4M over acircuit which may be traced from ground through the lower winding of the marginal relay 40 l, lower windingof back bridge relay tilt, front Contact and armaturel, front contact vand armature teli, wiper M9, bank contactASByconductor 507, called telephoneline, conductor 532, bank contact 49d, .wiper lit, armature E50 and its front contact,iarmature litt and its front contact,.upper winding of back bridge relay 400 and upper winding of marginal relay Mil to battery. 'I'he backbrid-gerelay itil and the marginal relay 4M are energized over this circuit. The relay mi upon operating prepares a point in the circuit of thedifferential relay tilt at armature 324 and at larmature 25 opens a point in the circuitof the upperwindingiof this relay. The relay '400 upon operating opens a point in the circuit of Ia supervisorysignal at armature 420, and its back contact, and4 at the front contact of this armaktureestablishes `a further locking circuit for the switching relay MQ, completes a circuit for the lower `winding of the differential relay 403 at armature 42H, and at armature 22 prepares a circuit for the upper winding o the diferential relay. Another result oiY the operation of the relay Mii! is that'at armature @23 a point in the circuit of the release magnet is opened and at the front` contact of this armature a point in the' circuit of a supervisor signal is established. The

circuitfor the lower "Winding of the differentialk relay 403 may be traced from ground by way of Afront' contact and armature l is, armature 42! and at armatures l2? and 328,respectively The reversalV of thec'onnections of the line relay as de- 'scribed'bring about'the operation of the timing switch VRS--L associated with the selector S as will be explained.v The circuit'for the motor magnet 464 may be traced from ground by way of lfrcint contact and armature llll,'armati1re 430 and its front contact, the bank contact with which the switch wiper 415 is in engagement when the switchRS-2 is in `normal or initial position, switch wiper M5, back contact and armature M5, and AVmotormagnet itil to battery; The motor magnet dell is operated over this circuit to ad- Vance the switch wipers 1513 to dit, inclusive, of the timing switch RS-2 into engagement with the second set of bank contacts. The operation of the timing switch R53-2 is thus initiated by the response of the called party at sub-station T-, but its operation has no lparticular 'function at the present time and the description of 'its operation will be left until it does function, whichfoccu'r's when the charge is to be assessed against the called line.l

`It is to be 'noted at this time' that when the switch wipers M6 to Ms, inclusive, of the connector switch C are brought into engagement with the bank contacts associated with the called line of the sub-station T-I, there was a circuit completed for the high resistance relay 402, if thiscall was made at certain periods of the day. This depends upon the operation of the clock switch M-I, which may be of any usual or well known type. It will be seen that the Wiper 46| of the switch M-l is adapted to connect battery to the common conductor 446, if the common conductor is tapped into certain bank contacts representing the hours of the day. Consequently, the periods during which battery is applied to this conductor may be regulated. 'I'he connection of battery to this conductor determines Whether or not the called party may reverse the charge by the use of instrumentalities at his sub-station. If battery is not connected to this conductor, he cannot alter the charge being assessed to the calling line. This may be desirable at certain periods of the day, as warranted by traic conditions,

It will be assumed in the present instance, however, that at the time thepswitch wipers of the connector were brought into engagement with the bank contacts of the called line battery was connected by the clock switch M-I to the common conductor 446. In this instance, there is a circuit completed for the relay 402, which extends from battery through the winding of the relay 402, front contact and armature 445, switch wiper 4|6, bank contact 492, conductor 500, meter 552 of the called line, associated with switch RS-3 to ground. The meter 552 is not operated over this circuit by reason of the high resistance of the relay 402. However, this relay is energized to prepare a circuit for the upper winding of the differential relay 403 at armature 426. This prepares a circuit by which the called line may reverse the charges.

Referring now to the description of the operation by which a time charge is assessed to the meter on the calling line, it will be recalled that the response of the called party brought about a reversal of battery over the conductors 391 and 398. This reversal of current flow brings about the operation of the electro-polarized relay 254 in the repeater R at the local exchange. The relay 254 upon operating completes a circuit for the relay 250 at armature 213 and at the armatures 21| and 212 changes the bridge across the talking conductors 280 and 28| to exclude the normally closed springs controlled by armature 269. The relay 250 upon operating the armature 262 completes a high impedance bridge across the trunk conductors 280 and 28| and at the armatures 260 and 26| reverse the connections of the line relay 25| with respect to the trunk conductors |91 and' |98. The bridge across the trunk conductors now extends from trunk conductor 280, armature 266 and its front contact, front Contact and armature 21| winding a polarized relay 254, front contact and annature 262, both windings of impedance relay 258, armature 212 and its front contact to trunk conductor 28|. This bridge circuit is of relatively high impedance so as not to affect the conversational circuit. The reversal of the battery connections over conductors |91 and |98 brings the current flow in the lower winding of the electric polarized relay |21 in the same direction as the current flow in its upper winding and this relay is energized to complete a circuit for the relay |26 at armature |43 and to complete a circuit at armature |45 for the motor magnet of the timing switch RS-L The circuit for energizing the motor magnet |58 extends from ground upon the release trunk by way, of armature |45 and its front contact, bank contact with whichthe switch wiper |6| is in engagement in normal position of the switch wipers, said wiper, back contact and armature |63 and motor magnet |58 to battery. 'I'he slow acting relay |26 upon operating prepares a circuit at armature |42 for the relay |25.

The motor magnet |58 is operated over the above traced circuit to advance the switch wipers |59 to |62 of the timing switch RS-I associated with the selector S, one step into engagement with the second set of bank contacts. The movement of the switch wiper |6| opens the previously traced circuit for the motor magnet |58. However, the operation of the switch wipers and more particularly the switch wiper |62 into engagement with the second set of bank contacts prepares a circuit for the operation of the motor magnet |58 which includes the interrupter or commutator |13 mounted upon the shaft |14 and connected to ground. As explained before, the shaft |14 is being constantly rotated ata predetermined speed, All bank contacts, except the last four and the rst one of the rotary switch RS-I are multipled together and connected to the armature |1| of the relay |10. Consequently, as the shaft |14 is rotated, ground is periodically connected to the winding of the motor magnet |58, which is periodically operated to advance the switch Wipers |59 to |62 over the bank contacts. The advancement of the switch wipers of the rotary switch RS-I continues as a result of the impulsing circuit to motor magnet |58 described, until the switch wipers are brought into engagement with the fourth from the last set of bank contacts, whereupon the impulsing circuit for the motor magnet |58 is transferred to the commutator |18 mounted upon the shaft |8|. This shaft is moving at a slower speed than shaft |14 and consequently the switch Wipers are not advanced so rapidly. Furthermore, during one revolution of the commutator |18, only one circuit is completed for the motor magnet |58, which further delays the advancement. When the switch wipers are brought into engagement with the third from the last set of bank contacts there will be a tone connected to the talking circuit over a path which extends from the tone machine by way of the conductor |9|, commutator |16, condenser |82, bank contact with which the switch wiper |60 is in engagement, armature |66 and its back contact, condenser |61, to the talking circuit. The tone machine connected to the conductor |9| gives a distinctive tone slightly in advance of the metering charge to apprise the vcalling party that a charge is about to be made. When the switch Wipers of the switch RS-I are brought into engagement with the second from the last set of bank contacts there is a circuit completed for the relay |10 Over a path which may be traced from the metering battery B through a commutator |11 when in the proper position, wiper |59, second from the last bank contact, and upper winding of relay |10 to ground. The relay |10 is energized over this circuit to establish a locking circuit through its lower winding to ground upon the release trunk conductor at armature |80 and to disconnect the bank contacts that control the periodic operation of the motor magnet |58 of the rotary switch vRS-I from the commutatorV |13 and connects themtothe commutator |72. Thepurpose of this operation is` for the reason that the usual practice in 4assessing telephone charges is to assess an initial charge for lan interval of time; thereafter to assess a charge for every minute or a shorter interval or" time. By reason of the number of segments on thecommutator |12 the switch wipers are stepped more rapidly to accomplish the difference in charges. The operation of the switch wiperv It@ into engagement with the second from the last bank contacts connectsrthe tone from the tone machine connected to the conductor igt to the talking circuit wherebythe calling subscriber isl apprised that his meter is being. operated .to assess the charge. The motor inagnetfl continues vto be operated periodically by reason oi the ground connection through the commutator |18. The purpose of switching the control-ofthe' motor magnet during the last four` steps of the meteringswitch RS-| is to provide for uniform operationof the switch over the last segments. This permits the tones to be applied to the talking circuit for a uniform interval,.irrespective oi therspeed of operation of the motor shaft i'lfl.

It should be mentioned at this time that the speed of the motor shaft iid may vary in accordance with the time of day, or yin accordance with traffic conditions in the exchange so as to provide a greater charge in the event that the call is made during-.a peak load or during ordinary load. l

v When the switch wipers are stepped into engagement with the last set of bankV contacts there is a metering circuit completed for energizing the meter lil'- orv the calling line. This circuit may be traced from the metering battery B throughthe c-ommutator iii, wiper |59, last bank contact, ,back contact and armature i, bank contact iifwiper` liti, front contact and armature ||5 and meter iti to ground. The meter il is operated over thiscircuit to assess a charge against the calling line.- Since an inter-cnice trunk line is being einployed'in this connection, the called subscriber is in a different Zone from the calling subscriber and it is necessary to arrange the meter charges to provide a dierent charge in` this class of 3 connection as before described. It will be seen 50- that there is a circuit completed in parallel with one that operates the meter lill that extends from the metering battery B, wiper its, 25th or last bank contact, back contact and armature |46, armature Mil and its front contact, wiper |35, bank contact lkconductor |95, relay 20G of rotary timing switch RS5, wiper 2|2 and rst bank contact l2 l5 to ground. The relay 29! isenerg-ized over this circuitvin parallel with the meter |91 and operates to complete a circuit for the relay 20| at armature 2531i and to open a point in the impulsing circuit at armature 265. VThe relay upon operating, establishes a locking circuit for itself at armature 2te, extends the metering circuit to the motor magnet ii at armature 2t?, prepares a metering circuit at armature ZMS Vand at armature i, disconnects battery from the bank contacts` accessible to the wiper EES other vthan the irstv one. The motor inagnet'iii is also operated over the metering'circuitbut since the switch wipers 2|2 to 2M, inclusive, are not actuated until the motor magnet 2id de-energizes, no operation occurs. -When the metering circuit is opened at the rotary switch RS4-I, the circuit for the slow acting relay 29|! and the motor magnet 218 is opened'and they are de-energized. The de-energization of the relay 2li@ occurs after a short interval of .time and prepares an impulsing circuit for the motor magnet 2|8. The motor magnet itis de-energized immediately upon the opening of the metering circuit to advance the switch wipers 2|? to 2MB, inclusive, one step into engagement with their second set of bmi; contact. The interrupter 225, after a short interval of time, completes another circuit for the meter lill and for the motor magnet 2|8 in parallel. This metering circuit may be traced from lthe metering battery B-i, armature 295, andgits back contact, armature 29S and its front contact, front contact and armature Zill, metering conductor m5, bank contact |85, switch wiper |35, front Contact and armature IM, bank contact |2i, switch wiper IMJ, front contact and armature H5 and meter |81 to ground, The meter ill 'is operated to assess an additional charge. rEhe motor magnet Zit is operated to advance the switch wipers 2|2 to 2M, inclusive, another step. At each revolution of the inter-V rupter 225, the metering battery brings about the operation ,of the meter on the calling line and the operation of the motor magnet 2|8. This continues until the proper charge is assessed on the meter itl associated with the calling line.` At this time the wiper 2id of the rotary switch RS--S will engage a bank contact to which ground is connected through the distributing frame DF. A circuit is thereupon completed for the relay Zl'?. The relay 292 is energized to open the locking circuit of the relay 29|. The relay 2li! is de-energizedto open the metering circuit and the stepping circuit at armatures 2t? and il, respectively, and to complete a release circuit at armature 2%9. This release circuit may be traced from battery by way of armature 7;!!9 and its back contact, bank contact with which the switch wiper 2l3 is in engagement, back contact and armature 2H 'and motor magnet Zit toground. Y

The motor magnet 2|8 is energized and since it interrupts its own circuit at arma-ture gi i, it is repeatedly operated a buzzer to bring the switch wipers 2|2 to 2M, inclusive, intovengagement with the first set of bank contacts. At this time, the circuit of the motor magnet is opened since battery is not connected to the bank contact Zit and the rotation of the rotary switch RS-5 will cease. f

' It will be seen that each time the calling subscribers meter ii'l is operated by the timing switch RS-i, the rotary switch RS- will be operated to assess an additional charge depending upon thev inter-exchange trunk line ernployed. That is, by connecting ground to any particular terminal on the distributing frame DF, the rotary switch RS-S may be stopped at any point in its operationso that the charge assessed against the calling line can be readily altered. All lthe rotary switches such as RS-E associated with trunk lines to common oices will have-a predetermined charge to add to= the original charge depending upon the exchange or Zone to which the call is made. 1

Gblviously, this provision is not needed in local exchange Y.calls when the timing switch RS-| associated with the rst selector'makes the local time charge. The provision of timing switches RS-l and RS-V-ii in the exchange in which the call originates is all the equipment necessary to provide for the charging of the calling subscriber in accordance with the zone in which the called line is located.

Returning now to the description of the operation of the rotary switch RS-|, it will be understood that during its operation which has been initiated by the removal of the receiver at the called telephone, subscribers may carry on their conversation. The operation of the rotary switch RS-I continues past the last set of bank contacts and the switch wipers |59 to |62 in their continued rotation are brought into engagement with their normal set of bank contacts. The operation of the switch RS-I continues in identically the same manner as described with the same results. Its operation during this second revolution is faster than the first by reason of the operation of the relay |10 previously described. The operation of the rotary switch RS-5 is initiated to assess an additional charge each time the meter |01 of the calling subscriber is actuated by the rotary switch RS-I.

In the usual course of events, the operation of the timing switch RS-I will continue until the calling subscriber replaces his receiver upon the switch hook at the end of the conversation and the meter |01 will be assessed in accordance with the time the telephone has been used and the rate, or rates prevailing during that period of time.

Under these conditions when the calling subscriber replaces his receiver, the line relay 25| in the repeater R is de-energized to open the circuit of the slow acting relay 252 and to open the bridge across the trunk conductors 280 and 28|.

The opening of the bridge across the trunk conductors 280 and 28| brings about the de-energization of the line relay 404 in the connector C and this relay will be de-energized to remove ground from the release conductor 396 whereby the switching relay 3|5 of the incoming selector S-I is de-energized. The de-energization of the switching relay 3|5 brings about its release in the manner already described.

In the repeater R, the de-energization of the slow acting relay 252 brings about the removal of ground from the release trunk conductor |96 whereby the switching relays |28 and the selector S and |08 in the line switch LS are de-energized. The de-energization of the relay |28 in the selector switch S brings about its release in the same manner as has already been described. In order to restore the wipers of the rotary switch RS-I to normal position, when the relay |28 is deenergized, there is a circuit completed which extends from ground by way of armature |5| and its back contact, armature |64 and its back contact, bank contacts engaged by the switch wiper |6|, back contact and armature |63 and motor magnet |58 to battery. This circuit serves to bring about the continued operation of the motor magnet |58 to adv-ance the switch wipers into their normal position. vThe removal of ground from the release conductor also opens the locking circuit of the relay |10 and this relay is de-energized to restore a connection of the commutator |13 and its associated bank contacts.

The rotary switch LS is restored to normal in the same manner as previously described. In the event the rotary switch RS-5 is not restored to normal at the time the calling subscriber hangs up, its release occurs in the manner described following the de-energization of the relay 202.

In the connector switch C, if the called subscribed has not yet placed his receiver upon the switch hook, the circuit oi' the release magnet is maintained open and the connector is not released until the called subscriber hangs up his receiver. The rotary switch RS-2 is, however, restored to normal by the connection of ground to the bank contacts accessible to wiper 415, which brings about the continued operation of the motor magnet 464 in an obvious manner. The switch wipers 413 to 416, inclusive, are rotated to their normal position. When the called subscriber hangs up there is a release circuit established for bringing about the release of the connector C, which may be traced from ground by way of armature 43|, and its back contact, armature 433 and its back contact, armature 423 and its back Contact, off-normal spring 451 and its working contact, back contact and armature 41|, and release magnet 4|| to battery. The release magnet 4| is operated over this circuit to restore switch wipers of the connector switch to normal. The de-energization of the relay 400 responsive to the called subscriber replacing his receiver brings about the de-energization of the relays 401 and 4|0 and theserelays retract their armatures to restore their respective circuits to normal.

Attention is directed to the fact that the selector switch S cannot be restored to normal until the rotary switch RS| is in normal position though if the calling subscriber replaces his receiver upon the switch hook immediately after the called party answers and before a charge is made or responsive to his initial tone. indicating a charge about to be made, the meter |01 will not be operated. This provision is made so that there will be no charge in the event a wrong number is obtained.

Attention is also directed to the fact that if the called subscriber does not immediately replace his receiver and the connector remains in operated position, ground is connected by way of armature 423 and its front contact to the supervisory signal to indicate this fact, and an attendant can remedy the situation, if the condiion persists.

It will be assumed that during the progress of the call between the sub-stations T and T-I, as before described, that the called party desired to have the charge assessed against his line and not against the calling line.

Under these conditions, the circuit, it will be assumed, is established as before, employing the line switch LS, selector S, repeater R, incoming selector S-| and connector C. It will be recalled that immediately upon the called subscriber at station T-l removing his receiver the relays 400, 40| and 403 in the connector and the relays |26 and |21 in the selectors were operated. As a result of these operations the rotary switches RS-l and RS-Z associated with the selector S and connector C respectively, begin to operate in the same manner as described. The charge will be against the calling line until the subscriber at sub-station T--l depresses his push button 566. When this occurs the shunt around the resistor 555 included in the line circuit is removed and the marginal relay 40| in the con-l nector C is de-energized. By the de-energization of this relay a point in the circuit of the lower winding of the differential relay 403 is opened and a circuit is provided for the upper winding of the differential relay 403, provided of course the metering switch or time switch M-l is in the ioE 35 and |45 of this relay are retracted. `The operaproper position with the relay 402 energized. The circuit for the upper winding of the differential relay 463 extends from ground by way of front.

contact and armature 4|4, front contact and armature 423, armature 422 and its front contact, armature 425 and its back contact, armature 426 and its front contact and upper winding of differential relay 403 to battery. The relay 403 is de-energized since current in both windings oppose. As a result of the de-energiaation of the relay 463, the connections of the line relay 464 with respect to the trunk conductors 391 and 398, is restored to normal. Another result of the operation of the relay 403 is that'an armature 429i in the circuit of both windings is opened. By the engagement of armature 436 of the relay 463 with its back contact, there is a circuit completed extend-ing from ground on release trunk conductor 396, armature 43E) and its back contact,

, back Contact and armature 411 and relay 453 to battery. The relay 463 is energized to establish a locking circuit for itself at armature 41B to open a point in the circuit of the release magnet at armature 41| to prepare a metering circuit g at armature 469 and to prepare a circuit at armature 468 forr applying tone to the talking circuit.

As a result of the reversal of connections of the line relay 404 of the connector as described by the de-energization of. the differential relay 463,

the current flow through the lower winding of the electropolarized relay |21 is again changed through the action of relay 25! in repeater R and opposesthe current flow in its upper winding. As a result of this operation, the armatures |43 tion of the armature |43 serves to complete a circuit for the relay |25 over a path extending from ground on the release trunk conductor, armature |43 and its back. contact, armature |42 and its front contact, and relay |25 to battery. Relay |25 is energized over this circuit to establish a locking circuit for itself at armature |39 to open a point in the circuit extending to the meter of the calling telephone at armature |40 to prepare a point in the release circuit at armature |4| and to open the connection by which tone through the'switch RS-I is applied to the talking circuit at armature |66. As a result of the energization of relay |25 the continued operation of. the rotary switch RS-l is ineffective. The operation of the relay |25 also opens the metering circuit extending back to the switch RS-li so that all further charges from this switch will cease.

When the called subscriber releases the push button 566, a shunt is again replacedv around the resistor 555 and the relay 46| in the connector is again operatively energized to attract its armatures 4.24, 425 and 411. The operation of its armature 425 opens a point in the circuit of the upper Winding of. the differential relay 453, while the operation of the armature 411 opens a point in the circuit of the relay 463. The operation of the armature 424 serves to again establish a circuit for the lower winding of the differential relay 463, whereby the connections of the line relay 4.64 with respect to the talking conductors 391 and 398 is again reversed. The reversal of these connections again brings about the energization of the electropolarized relay |21 in the selector S through the action of relay 256 in the repeater R, but its operation has no particular function at this time.

vlltY will be recalled thaty when the relay 463 was originally energized, the motor magnet 464 of the rotary switch RS2 was operated and that the wipers of the rotary switch RS-Z were advanced one step into engagement with thesecond set of bank contacts. By this advancement the original circuit foithe motor magnet is broken at the wiper 415 and another circuit was established for this magnet, which extends by way of the wiper 416, second setrof bank contacts, armature 461 and its back contact and commutator 435 on the shaft 439 to ground. The motor magnet is periodically operated by the operation of. the commutator 485 advancing the switch wiper step by step at a definite rate'of speed. When the switch wipers are brought into engagement with the fourth from the last set of bank contacts, the circuit for operating the motor magnet above described is switched to the commutator 481 on the shaft 433, which moves uniformly. When the switch wipers are advanced into engagement with the third from the last set of bank contacts, if the subscriber of the called sub-station has depressed his push button at this time to bring about a reversal of charges, a tone from the tone machine 430 is applied to the talking circuit over a path that may be traced from the tone machine, commutator 483, third from the last set of bank contacts, wiper 414, front contact and armature 468, condenser and thence to the talking circuit. This tone apprises the subscribers that a charge is about to be made. The tone maybe of different pitch, than the tone connected either to the conductors |99 or |98 associated with the selectors, and apprises the subscribers the charge is to be made against the called telephone. When the switch wipers are advanced into engagement with the second from the last set of bank contacts, the tone from the tone machine 43| is connected to the talking circuit and will apprise the subscribers that a charge is being made against the called telephone. As before described, the shaft 488 of the metering equipment M--2 may be driven at varying rates, depending upon the time or traffic conditions to make a charge in accordance with the amount of traic in the ex change or in accordance with the time of day.

When the switch wiper 413 is brought into engagement with the last set of bank contacts there is a metering circuit completed, which extends from the metering battery B|, commutator 434, wiper 413, last bank contact, front Contact and armature 465, front contact and armature 418, front contact and armature 445, wiper 4|4, bank Contact 462, conductor 566, and meter 552 assocated with the line switch of the called telephone to ground. The meter 552 is operated to assess the charge against the called telephone.

When the switch wiper 413 was in engagement with the second from the last set of bank contacts there was a circuit completed for the upper winding of the relay 462. The relay 462 is energized to establish a locking circuit for itself at armature 466, which extends to release trunk ground, and connects the impulsing circuit through the commutator 486 to provide that faster operation of the timing switch RS-2 during its second operation may be had. So long as the subscribers at sub-stations T and T-I are in communication, the time charge will be assessed against the called telephone in accordance with the traffic conditions.

In order to make an additional charge against P ner described, another circuit is completed over the metering trunk conductor which may be traced from the metering battery commutator 484, wiper 413, last bank contact, front contact and armature 469, armature 418 and its front contact, trunk conductor 365, bank contact 340, wiper 336 of selector switch S|, armature 3 I 4 and its front contact, slow acting relay 350, wiper 362 and bank contact 365 to ground, the slow acting relay 356 is energized to complete a circuit for the relay 35| at armature354 and to open a point in the metering circuit at armature 355. The relay 35| is energized to establish a locking circuit for itself at armature 356 to complete a circuit for the motor magnet 368 at armature 351 to prepare a metering circuit at armature 358 and to open a point in the release circuit at armature 359. When the relay 402 of the connector C was energized upon connection being made with the called line, a circuit was completed in parallel with the meter 552 extending to the line relay 350 of the switch RS-S. However, by reason of the high resistance of the relay 402 included in this circuit the relay 350 was not energized. When the I above traced metering circuit is opened, the circuit of the slow acting relay 350 and the motor magnet 368 is opened and they de-energize. 'Ihe de-energization of the motor magnet 368 serves to advance the switch wipers 362 to 364, inclu'- sive, into engagement with the second set of bank contacts. The movement of the switch wiper 362 out of engagement with its normal bank contact 365 opens another point in the circuit of the slow acting relay 350. The slow acting relay 353 is de-energized after a short interval of time to open the original circuit for the relay 35| at armature 354 and to prepare a new metering and impulsing circuit at armature 355. For each revolution of the interrupter 315, a battery is connected to the motor magnet 366 to bring about its interrupted operation and the advancement of the switch wipers 362 to 364, inclusive. At each revolution of the interrupter 315, there is an additional circuit completed for the meter 552 associated with the called line over a path that may be traced from the metering battery through the interrupter 315, armature 355 and its back contact, armature 358 and its front contact, front contact and armature 351, front contact and armature 3I4, wiper 336, bank contact 340, metering conductor 395, front contact and armature 445, wiper 4|6, bank contact 492, trunk conductor 50|) and meter 552 to ground. The meter 552 is thus yoperated to assess an additional charge against the called line in accordance with the rtones that the subscribers at sub-stations T and T--I are located in.

When the proper charge is assessed, the switch wipers 362 to 364, inclusive, will be advanced to the set of bank contacts at which the wiper 364 engages a ground potential through the distributing frame DF-L At this time there will be a circuit completed for the relay 352 which, upon operating, opens the locking circuit of the relay 35|. The latter relay is de-energized to open the metering circuit at armature 351 to open the impulsing circuit at armature 358 and to complete a release circuit at armature 359. This release circuit brings about the rapid step by step action of the motor magnet 368 until the switch wipers 362 to 364, inclusive, are advanced to their normal position.

In this manner, after each charge is assessed against the calling line from the rotary switch RS-2 associated with the connector C, additional charges are assessedv against the called line depending upon the Zones that the subscribers are located in.

Obviously, by means of the distributing frame DEL-I, any assessment desired may be made against the called line and it may be the same or vary from that assessed against the calling line in the manner described should it be desired to penalize the called subscribers employing this SelVlCe.

It will be seen that there is an additional charging switch associated with each inter-office trunk line at both the outgoing and incoming ends and these switches will function to add additional charges to the calling or called lines, depending upon the zones that the two subscribers are in.

It will be perfectly obvious that if the trunk lines should be of the two-way type that no additional rotary charging switches need be associated with them. That is, in two-way trunk lines the rotary charging switches into each exchange will function equally well on calls in either direction. These additional charging switches may well be termed "surchargers.

It will be seen that this additional zone metering charge is directly variable in accordance with the time of day and the various conditions affecting local charges as already explained.

In local calls, it will be obvious, of course, that no surchargers will be necessary but that the subscribers may reverse the time charges from the calling to called telephone, as desired.

When the conversation is nished, the subscribers will replace their receipers upon their respective switch hooks and the various switches employed in the connection will be restored to normal in the manner already described.

Attention is directed to the fact at this time that in the event the called subscribed hangs up and the calling subscriber maintains the connection, the de-energization of the relay 400 re sponsive to the replacement of the switch hook at the called telephone opens the metering circuit at armature 418 so that the calling subscriber cannot make an unfair charge against the called subscriber.

When the conversation is terminated, the subscribers will replace their receivers upon their respective switch hooks. As a result of the replacement of the receiver at the calling station, the line relay 464 in the connector C will be deenergized and the slow acting relay 405 will be de-energized a short time thereafter to remove ground from the release trunk conductor 396,.

thereby bringing about the release of the incoming selector S-I in the manner already described.

At the local exchange, the line relay of the repeater R is de-energized to open the circuit of the slow acting relay 252 which is deenergized to remove ground from the release trunk conductor |96, thereby bringing about the release of the line switch LS, selector S and the restoration to normal of the timing switch RS-i individual to the selector in a manner similar to that already described. The de-energization of the relay 405 in the connector C also causes the timing switch RS-Z to be restored to normal by applying ground to the bank contacts accessible to the wiper 415 of the rotary switch RS-2. This ground connection causes the motor magnet 464 to operate to rotate the switch wipers 413 to 416, inclusive, to normal position. When the called subscriber at sub-station T-l hangs up, the circuit for the release magnet 4|| is completed and the connector switch C is rele-ased in a manner similarV toVV that already described.

From the foregoing it will be seen that there is a time charge made against the calling line upon theV response of the called line under the control of a rotary switch, such as RS-I individual to the selector used. It is desirable that the rotary switches such as RS--I be rotated relatively rapidly under the control of the impulring device |13, somewhat more rapidly under the control of the impulsing device |12. This arrangement should be so that the initial rotation of the rotary switch RS-I will occur in approximately twenty seconds, though this period may be varied as desired, and that the second rotation will occur at a relatively faster speed. This provision should be made in order that the calling subscriber cannot hold a conversation with the called subscriber for any particular period of time for the charges made. The meters such as |91 and 552 can be regulated to make the proper charge for the usual number of operations.

In a like Vmanner the switches such as RS-2 associated with the connector should be arranged to rotate at substantially the same speed as the timing switches RS-I. The surchargers RLS- 5 and'RS-G are operated to bring about the additional zone charge -against the calling or called subscribers in the manner described immediately following the assessment of the usual charge against either calling or called telephone in the manner described. Y

It will `be seen that the charges madeto the called subscribers line at his option will be in accordance with the time the telephone talking circuit is in use, the time of day at which the call is made and the rate prevailing at that time and the zones in which the subscribers are located. Attention is also directed to the fact that means are provided for indicating to the subscriber, irrespective of their zones, which` line the charge is being assessed against and also when the charge is made.

The telephone sub-station T2 is somewhat modified so that instead of the push button such as 551 removing the short circuit about a resistor, the depression of the push button grounds one side of the line. This grounding may be employed to operate a relay such as 40| in the connector of the differential type instead of a marginal relay in an'obvious manner. Under these conditions, the resuits will be identical with those described.

In a metering system such as has been described it is desirable that certain telephone lines such as those belonging'to the telephone company be arranged for a free charge, so that no charge will be made to the calling party in the event connection is made with -any of these lines. In order to accomplish this result, the line extending to a free telephone is provided with the relay equipment associated with the line switch such as RS-M. The bank contact which ordinarily would be connected to the meter in the Aand particularly the diierence between this kind Y of a cali anda vregular cali will now be described. In establishing the connection from the calling telephone T to the called telephone T-'3 of the free class, line switch RS of the call-ing line and a selector 'such as S, repeater R, selector S--I and a connector such as C,`willbe operated in identically the same manner as before described to establish the connection. It will be assumed that the selector switch S, repeater R, selector S-I and the connector C are the ones employed to establish the connection. Connector switch C will be operated so as to bring its wipers 4|6 to 4|9, inclusive, into engagement with the bank contacts 491 and 495 and 499, respectiv-ely. The bell at the substation T-Zt will be operated periodically to summon the subscriber thereat. When the party at the telephone T-3 removes his receiver from the switch hook, the ring cut-off relay Lidi is energized to establish a locking circuit for self at armature 431 and connect the called line to batt-ery through the backbridge relay 400 and the marginal relay 40|. Both these relays operated with the same results as before. The differential relay 403 is alsoenergized to reverse the connections of the line relay 404 with respect to the trunk conductors 397 and 398. 1t will be seen that the relay 5 I 9 is included in the line circuit of the called telephone in parallel with a non-inductive resistance so as to provide a clear path for voice currents, and partially to short circuit the relay 5|9 when ringing current is applied. Relay 5|9 is adjusted not to respond to ringing curr-ent, however, the relay 5|9 is energized in series with the relays 409 and 49| of the connector. The relay 5 9 upon operating completes a circuit for the slow to operate relay 5|8, and the relay 5|8 is made slow to operate to give the relays 499 and 49|, as Well as the relay 403, time to operate before this relay is energized. The operation of the relay 5 8 serves to complete a circuit for the relay 5 i l at armature 533 and to open the short circuit around the resistor 536 at the armature 535. The removing of the short circuit around tl'i-e resistor 536 includes this resistor Vin the circuit and permits th-e marginal relay 49| in the connector C to de-energize to retract its armatures. The relay 5|? upon energizing, opens `a point in the circuit of the relay 5|8 at armature 55| and completes a locking circuit for itself at armature 532 to ground upon the release trunk conductor 506. The relay 5|8 is de-ener- .gized after an interval of time-to open the original energizing circuit of the relay 5I1 and to again short circuit the resistor 536.

In the connector switch C the relay 40| upon cle-energizing, completes a circuit for the upper winding of the differential relay 453. The differential relay 493 retracts its armatures again to reverse the connections of the line relay 404 with respect to the trunk conductors 391 and 398, thereby bringing about the retraction of the armature 2*!3 of the electropolarized relay 254 in the repeater R and this brings about the de-en-ergization of the relay 250 and the consequent reversal of the connections of the line relay 25| with respect to the trunk conductors |97 and |98, thereby bringing about the energization of therelay |25 in the selector switch S. The operation of this relay renders the functioning of the timing switch RS--I individual to the selector ineffective, it being remembered that this switch was started by the operation of the electropolarized relay i'ii responsive to the first reversal of current over the conductors. The operation of the diierential relay 493 brings about the energization of the relay 453 and brings the timing switch IRES-2 into play. However, since the metering Wiper 4I4 extends to ground through a resistor by way of the bank contact 493, the metering switch RS-Z is ineffective to assess any charge, there being no meter connected with the telephone T-3, as it is an official or free telephone. In this manner, no charge is made to the calling subscriber when he calls a free telephone number.

When the conversation is terminated the connection is released in a manner similar to that already described. y

It is possible in a telephone system of this character that some of the lines other than company lines may not be provided with meters, but be operating on a flat rate basis. In this instance there will be no meter connected to this class of lines. The meter bank contacts 493 in the various connectors having access to this class of lines are simply left open. The purpose of leaving these bank contacts open is to prevent the called party exercising any control whatsoever over the ymetering charge. It will be seen that if the bank contact such as 493 is left open there is no circuit that may be completed for the relay 402, which controls the de-energization of the differential relay 403, the relay 350 being of sufficiently high resistance to prevent the operation of the relay 402. Consequently, a called party having such service could not by any manipulation or appliance on his telephone line cause the disconnection of the metering charge to the calling party, which he might do were it not for this provision.

From the foregoing, it will be obvious also that a certain amount of the charge may be assessed against the calling line and thereafter further charge may be made against the called line, depending upon the time at which the called party exercises his reverse control.

The clock switch M-I provides means by which, during certain hours of the day, a certain group of lines or all lines in the exchange may not have this reverse service.

It will be obvious that the surchargers or rotary timing switch may be used where no reverse metering is employed for the purpose of bringing about a toll charge Where toll calls are made or where calls are made to subscribers in exchanges in different zones than that of the calling subscriber. A very great advantage of this construction is`that the surcharging switches may be inserted at any point in the connection in association with any other class of switches to add any desired number of impulses to an impulse train and that only one trunk wire is necessary for its functioning. This greatly reduces the amount of equipment ordinarily required for zone metering puiposes and particularly where time charges are made. Ordinarily to make proper zone meter charges, it is necessary to employ some articial means such as a director or translator whose cost is large both as to original cost and maintenance. However, while employing the rotary switches or surchargers at the desired point in the connections, the regular exchange equipment may be employed and at the same time, all advantages as to flexibility may be obtained. Attention is directed to the fact that the surchargers cannot function until the local metering charge is made and that there can be no interference between them.

Having described certain specific embodiments of my invention, I am aware that many changes, departures and deviations may be made therefrom' Without departing from the spirit and SCOpe thereof, as indicated in the appended claims;

, I claim:

l. In an Aautomatic telephone system, the combination of telephone lines terminating in a plurality of exchanges, a metering device associated with each telephone line, means including automatic switches and two-conductor trunk lines for establishing a connection between a calling and called one of said lines, said trunk lines including only two conductors, and means controlled from one of the telephone lines after the connection is established for operating the metering device on either the calling or called lines as a result of the establishment of the connection.

2. In an automatic telephone system, the combination of telephone lines terminating in a plurality of exchanges, a metering device associated with each telephone line, means including automatic switches and two-conductor trunk lines for establishing a connection between a calling line in one exchange and a called line in another exchange, said trunkY lines including only two conductors, and means controlled from one of the telephone lines after the connection is established for operating the meter on the calling or called line over a part of said connection.

3. In an automatic telephone system, the combination of telephone lines terminating in a plurality of exchanges, a metering device associated with each telephone line, means including automatic switches and two-conductor trunk lines for establishing a connection between a calling line in one exchange and a called line in another exchange, said trunk lines including only two conductors, and means controlled from one of the telephone lines after the connection is established for operating the meter on the called line as a result of the establishment of the connection between the lines.

4. In an automatic telephone system, the combination of telephone lines terminating in a plurality of exchanges, a metering device associated with each telephone line, means including automatic switches and two-conductor trunk lines for establishing a connection between a calling line in one exchange and a called line in another exchange, said trunk lines including only two conductors, and means for operating the meter on the called line under the control of the subscriber thereat as a result of the establishment of the connection.

5. In an automatic telephone system, the combination of telephone lines terminating in a plurality of exchanges, a metering device associated with each telephone line, means including automatic switches and two-conductor trunk lines for establishing a connection between a calling line in one exchange and a called line in another cxchange, said trunk lines including only two conductors, and means for periodically operating the meter on either the calling or called line according to the period of the connection while said connection is maintained.

6. In an automatic telephone system, the combination of telephone lines terminating in a plurality of exchanges, a metering device associated with each telephone line, means including automatic switches and two-conductor trunk-lines for establishing a connection between a calling line in one exchange and a called line in another exchange, said trunk lines including only two conductors, and means controlled from one of the telephone lines after the connection is established for periodically operating the meter on the called line while said connection is maintained.

7. In an automatic telephone system, the com- `lai-nation of telephone lines-terminating in a plurality of exchanges, a metering device associated with each telephone line, means including automatic switches and two-conductor trunk i lines for establishing a connection between a calling line in one'exchange Vand a called line inl another exchange, said trunk lines including only two `conm ductors, and means for periodically operating the meter on either the calling or called line while said connection is maintained at the option of the subscriber on the called line.

8. In an automatic telephone system, the combination of telephone lines terminating in a plurality of exchanges, a metering device associated with each telephone line, means including autormatic switches and two-conductor trunk lines for establishing a connection between a calling lineY in one exchange and a called line in another exchange, said trunk lines including only two conductors, means for operating the meter asso cia-ted with the calling line during a portion of the time that the connection is established, and means for operating the meter on the called line during another portion of the time that the con- Anection is maintained.

9. In an automatic telephone system, the co1n-k bination of telephone lines terminating ina plurality of exchanges, a metering device associated with each telephone line, means including automatic switches and two-conductor trunk lines for establishing a connection between a calling Y `Ii-ne in one exchange and a called line in another exchange, said trunk lines including only two conductors, means for operating the meter associated with the calling line during a portion of the time that the connection is established, and means for operating the meter on the called line during another portion of the time that the connection is maintained, said means being controlled from 'the called line.

10. In an automatic telephone system, the cornbination of telephone lines terminating in a plu rality of exchanges, means including automatic Vswitches for establishing a connection between a calling line in one exchange and a called line in another exchange, and means for signaling the subscribers on said lines to indicate the line that is assessed with the charge.

11. In an automatic telephone system, the combination of telephone lines terminating in a plurality of exchanges, a metering device associated with each telephone line, means inclu-ding automatic switches and two-conductor trunk lines ior establishing a connection between a calling line Iin one exchange and a called line in another ex change, said trunk lines includingronly two conductors, means for operating the meter associated.V

with the called line periodically while said connection is maintained, and means for varying the periods of time between said meter operations.A

12. In an automatic telephone system, the cel bination of telephone lines terminating in a plurality of exchanges, a metering device associated with each telephone line, means including auto-- matic switches and two-conductor trunk lines for establishing a connection between a calling line in one exchange and a called line in another exchange, said trunk lines including only two conductors, means for operating the meter associated with the called line periodically while said connection is maintained, and means for varying the periods of time between said meter operations depending upon the time of day during which rthe connection is established.

13. In an automatic telephone system, the combination of a pair of automatic telephoneV exchanges, telephone lines terminating in each exchange, a metering device associated with each line, means including automatic .switches for establishing a connection between a line in one exchange and a line in another exchange, means for operating the meter associated with the called line periodically while said connection is maintained, and means for varying the periods of time between meter operations depending upon whether the call is from the lines in the same exchange or between exchanges to make a charge on the meter which varies depending upon whether the call is between lines in the same or dilerent exchanges.

lli. In an automatic telephone system, the combination of a pair of telephone exchanges, telephone lines terminating in each exchange, a metering device associated with each line, means including automatic switches and two-conductor trunk lines for establishing a connection between a line in one exchange and a line in another exchange, said trunk lines including only two conductors, means for operating the meter on either i the calling or called lines as a result of the establishment of the connection at the option of the subscriber on the called line, and means op erative during certain intervals of time for preventing the operation of the meter on the called line.

l5. In an automatic telephone system, the combination ofa pair of telephone exchanges, telephone lines terminating in each exchange, a metering device associated with each line, means including automatic switches and tivos-conductor trunk. lines for establishing a connection between any two of said lines, said trunk lines including only two conductors, and means for operating the meter associated with either line at the option of the subscriber on the called line.

16. In an automatic telephone system, the combination of a pair of telephone exchanges, telephone lines terminating in each exchange, a metering device associated with each line, means including automatic switches and two-conductor trunk lines for establishing a connection between any two or said lines, said trunk lines including only two conductors, and means controlled from one of the telephone lines after the connection is established -fcr operating the meter associated with either line as a result of the establishment of the connection.

17. In an automatic telephone system, the combination of a pair of telephone exchanges, telephone lines terminating in each exchange, a metering device associated with each line, means including automatic switches and two-conductor trunk lines for establishing a connection between any two of said lines, said trunk lines including only two conductors, and means for periodically operating the meter associated with the called line while the connection between the lines is maintained.

18. In an auto-matic telephone system, the com bination of a pair of telephone exchanges, telephone lines terminating in each exchange, a metering device associated with each line, means including automatic switches and two-conductor trunk lines for establishing a connection between any two of said lines, said trunk lines including only two conductors, means for operating the meter associated with the called line periodically while said connection is maintained, and means for varying the periods of time between said Iil) 

